The T-coil or Telecoil (for Telephone Coil) is a common hearing aid component that allows hearing aid wearers to hear clearly on the telephone. The T-coil, basically a short coil of wire wrapped abound a metallic core, responds to the same fluctuating magnetic field that drives the speaker in a telephone handset. When it is activated, the hearing aid amplifies the signal from the T-coil instead of amplifying the signal from its microphone. The sound is clearer to the user because the magnetic field from the handset does not contain the extraneous noise picked up by the hearing aid's microphone.
Hearing loops, audio induction loops, or audio-frequency induction loops are systems which engage a user's T-coil to assist the user in hearing. A hearing loop system is a loop of wire or cable, or an array of cable loops, installed around a designated area or a room. Locations where hearing loops are often found include teller windows, drive-ins, and, routinely, large recital halls. The loop or loops create a magnetic field from an electronic sound source, such as a microphone, a video player, a TV, a telephone, and, indeed, any sound system. The magnetic field contains the same sound information as does the voice coil driving the speaker in a telephone handset, but over a wider area for people with T-Coils in their hearing aids.
According the NIH, “an estimated 17 percent of American adults report having some form of hearing loss. Nearly half of adults ages 75 years and older have hearing loss.” The NIH estimates that only 1-in-5 people who need hearing aids use them. And, of course, almost everyone has trouble hearing in noisy environments or large spaces like theatres and classrooms. Public address and sound reinforcement systems help, but hearing aids used with hearing loop systems are superior. And, hearing loop systems are becoming more common every day.
A device which is also becoming more common among the general public is the smart phone. Besides providing a mobile telephone, the smart phone provides entertainment to the user, i.e., games, video, sound recordings, etc., a connection to the Internet with the ability to send and receive data over that network with the ensuing features attached to the Internet, and a host of other functions. The cost of a smart phone, typically hundreds of dollars, is much less than that of a hearing aid, typically thousands of dollars, making a smart phone much more economically available. A boon to the growing population of the elderly and other people with hearing impairments is the incorporation of the T-coil into the smart phone. Furthermore, the incorporation should not interfere with the existing functions and abilities of a smart phone.